Adult ADHD - The Challenges of Diagnosing and Treating

Adult ADHD - The Challenges of Diagnosing and Treating

Once thought only to affect children, attention-deficit hyperactivity disorder (ADHD) is now known to persist into adulthood.1-3 Almost half (46%) of adults who had ADHD as children continue to have symptoms of the disorder as they age, with almost all of them (95%) experiencing attention-deficit symptoms and about 35% of them experiencing hyperactivity-impulsivity symptoms.4 Although the disease is highly treatable, 90% of those with symptoms of ADHD are untreated and continue to have major impairments in multiple domains of functioning.5 In a survey of 500 adults diagnosed with ADHD that compared their functioning with a comparable non-ADHD sample representative of the U.S. population, adults with ADHD were significantly:6

Less likely to have graduated high school (83% vs. 93% of controls; P≤0.001), obtained a college degree (19% vs. 26%; P<0.01), be currently employed (52% vs. 72%; P≤0.001), and satisfied with their lives in general (P≤0.001)

More likely to have multiple job changes (5.4 vs. 3.4 jobs over 10 years), to have been arrested, (37% vs. 18%), and to have been divorced (28% vs. 15%; P≤0.001 for all comparisons).

Comorbidities can complicate the diagnostic picture
Because no objective, laboratory-based tests exist that can establish a clinical diagnosis of adult ADHD, and because ADHD is often comorbid with other psychiatric problems,7 the DSM-IV, is used to evaluate adult patients who exhibit ADHD-like symptoms. Diagnostic indicators include the results of a clinical interview, rating scales to assess current symptoms, reports from parents, siblings, or significant others about childhood or adulthood behaviors and poor psychosocial outcomes (eg, relationship problems, employment gaps).

Adults with ADHD often have DSM-IV comorbidities, which blur ADHD symptoms, making diagnosis and treatment difficult. The National Comorbidity Survey Replication (NCSR) study, a nationally representative household survey that assessed 3,199 people ages 18–44 years showed that of adults with ADHD:5

Almost 1 in 2 also had an anxiety disorder, typically social phobia

Over 1 in 3 had a coexisting mood disorder, mainly depression and bipolar disease

One in 5 had intermittent explosive disorder

Almost 1 in 6 had a substance use disorder

Thus, adults presenting with ADHD symptoms, or any concurrent psychiatric symptoms, should receive a full spectrum clinical interview to unveil comorbidities.

Gender differences in symptomatology to consider when diagnosing
Research in the last decade has also revealed that ADHD symptomatology differs according to gender. In childhood ADHD, boys have the combined type with more frequent externalizing behaviors, while girls have the inattentive type with more frequent internalizing disorders.8,9 In other words, boys can be more raucous and rebellious while girls tend to withdraw. These gender differences are also apparent in adult ADHD. Often, it is the symptoms of the adult female with ADHD that are more difficult to unmask because of their internalized nature. A retrospective data analysis in which 34% of the adults were female showed that women:10

Were rated as more symptomatic on every measure of ADHD symptoms including total Conners' Adult ADHD Rating Scale-Investigator Format (CAARS-INV), total Wender-Reimherr Adult Attention Deficit Disorder Scale (WRAADDS), and most subscales of both measures

Were more likely to have combined type ADHD (75% vs. 62%)

Showed a more complex presentation, with higher scores on the Hamilton Rating Scale for Anxiety (HAM-A) and the Hamilton Rating Scale for Depression, 17-item version (HAM-D[17]), more sleep problems, and more past DSM-IV Axis I diagnoses

For these reasons, an assessment of adults – both women and men – should include an examination of the emotional extent of the illness.
Treatment of adult ADHD
Treatment for adult ADHD is becoming parallel with treatment for childhood ADHD as clinical studies are now both including and highlighting treatment efficacy in adults, with the FDA granting indications for use in adult patients. Currently, long-acting psychostimulants such as methylphenidate, mixed amphetamine salts, lisdexamfetamine as well as non-stimulants are used in the treatment of ADHD. Although psychostimulants have been shown to be effective and safe for the treatment of ADHD, approximately 30% of those who are prescribed stimulants for ADHD either do not respond to or do not tolerate these treatments.11

Non-adherence to medication due to the array of related side effects – insomnia, tics, mood swings, aggression12 – is a notable reason for treatment failure. While more studies have focused on ADHD medication adherence in children/adolescents than in adults, studies of pharmacy claims databases and treatment studies have revealed that the prevalence of medication discontinuation or non-adherence ranges from 13% to 64% when all age groups are considered.13

In addition, stimulants carry risk for abuse potential. For this reason, patients with substance abuse problems need to be closely monitored with respect to their prescribed medication use. However, meta-analyses of 13 studies have demonstrated that the use of stimulant ADHD therapy does not increase the risk for developing substance use disorders but is, in fact, protective against it.14,15 Stimulant treatment of ADHD early in life appears to reduce the risk for future substance use disorders by 50%.15

Despite the data supporting a protective effect of stimulants against substance abuse disorders, the enduring concern about the abuse and diversion potential of stimulants15,16 as well as adverse reactions of current therapies reinforce the value of assessing new treatments for ADHD, and non-stimulant therapies (ie, atomoxetine, guanfacine, clonidine) in particular. Nevertheless, non-stimulants are not devoid of serious side effects. The only non-stimulant approved by the Food and Drug Administration (FDA) for use in adults with ADHD is atomoxetine, a selective norepinephrine reuptake inhibitor.17 Atomoxetine has a black box warning regarding suicidal ideation and has been associated with rare cases of severe liver injury and sudden cardiac events from post-marketing reports.17 Contrarily, recently published reports have demonstrated that neither stimulants nor non-stimulants increase the risk of serious cardiovascular events in young and middle-aged adults.18,19 Yet, the use of these drugs must continue to be considered on a patient-by-patient basis, particularly in the older patient who may have one or more chronic cardiovascular conditions. Such patients should be screened for cardiac abnormalities prior to initiation of ADHD medication.

Adult ADHD is not necessarily treated with pharmacotherapy alone. The results of recent research provide solid evidence that psychological approaches, notably cognitive behavioral therapy (CBT), amplify the effect of medication treatment in reducing ADHD symptoms and comorbid problems, and demonstrate improvements in functions associated with impairment.20 Such findings support the recommendations of guidelines for a comprehensive treatment package that includes psychological and pharmacological treatments for adults with ADHD.21

More research is needed to understand the continuum of ADHD throughout the lifespan and whether persistence into adulthood can be curtailed with medication use in childhood.